HTML Preview Broken (build 5661)

I have some web pages that use the CSS shown below. The "content" division should be adjacent to the "navigation" division but is instead shown below it in the HTML preview.

Donald
-

div


ul


h1, h2, h4, h5, h6


h3


li.here


p.bold
{
font-weight:bold;
}

td.text
{
text-align: center;
}

td.numeric
{
text-align:right;
}

tr.footer
{
font-weight:bold;
}

#header
{
background-color: Black;
color: White;
}
#header
{
background-color: Black;
color: White;
}

#navigation
{
background-color: #0099FF;
float: left;
width: 150px;
}

#content


#footer